The present invention relates to the field of archery and specifically to time delayed bowstring release devices used to mechanically release the bowstring for greater accuracy.
Improvements in technology within the field of archery have brought about many changes in bows and shooting technique. Compound bows shoot at a much faster speed than the older recurves and straight bows. The faster speeds have brought about a much greater need for accuracy. Accuracy is directly affected by the manner in which the archer releases the arrow. Historically, archers used their fingers to release the arrows. This proved to be very difficult due to the fact that there was inconsistency in the way that the bowstring would come off the ends of the fingers. As technology changed, archers began to utilize mechanical release devices. These devices provided much greater accuracy because the release was very consistent.
A psychosomatic reaction commonly referred to as xe2x80x9ctarget panicxe2x80x9d is a phenomenon that takes place when the archer flinches at the exact time of release of the arrow, thus adversely affecting the destination of the shot. The psychological anticipation of shock coming from the bow release causes this uncontrollable reflex. Many products have been developed to help alleviate this problem. However, most of the products involve some physical force on the part of the archer to release the arrow.
Many bowstring release devices currently exist that utilize a trigger pull mechanism to fire the bow. These mechanisms require that the archer apply a steady pressure without any target panic. By way of example, U.S. Pat. No. 5,224,463 to Townsend discloses a manually-operated bowstring release device and U.S. Pat. No. 5,546,924 to Todd discloses a similar apparatus using a roller device.
Other devices are in existence that involve a hinge release mechanism in which the archer exerts a back pulling motion to release the arrow. These devices are generally classified as back-tension releases. These devices involve a physical pulling action on the part of the archer. The archer does not have an exact awareness of exactly when the bow will fire. While there is significant improvement over trigger release devices, there is still the possibility of target panic or jerking the device.
Electronic time delay bowstring release devices allow the archer to activate a switch to activate the device. The time delay is performed electronically and is adjustable and available with a random delay feature. For example, U.S. Pat. No. 5,494,023 to Kolak discloses a bowstring release apparatus using an electrical time delayed release device and U.S. Pat. No. 5,575,269 to Harklau discloses an electronic time delay with a random delay feature. The electronic time delay devices were found to be less reliable, and in some cases, were considered unsafe for use by some archers. The batteries used to operate these devices tended to expire without warning and many times caused inconsistency and even failure in operation during critical shots.
The present invention provides a pneumatic time delayed bowstring release apparatus having a safer operation and more reliable function than prior art devices. The present invention incorporates all of the advantages of a time delayed operation, except for the randomizing function that is not considered by some archers to be an advantage. The apparatus does not rely on batteries that expire without warning or cause inconsistency in timing of the operation of the apparatus.
The invention is a pneumatic time delayed bowstring release apparatus for use with a bowstring affixed to a bow. The apparatus comprises a housing, a pair of caliper release heads pivotally connected to the housing and designed to receive and hold a bowstring, a trigger pivotally connected to the housing, a wedge-shaped plate having an integral groove for slidably moving along a spline track in the housing, a spring to bias the caliper heads in an xe2x80x9copenxe2x80x9d position, a pneumatic chamber, a pneumatic piston pivotally connected at one end to the trigger, an air relief vent, a spring to bias the piston in an xe2x80x9copenxe2x80x9d position, and an adjustable air intake control valve.
In operation, the archer depresses the trigger which pivots a portion of the trigger into the wedge-shaped plate and thereby forces the wedge-shaped plate into engagement with the ends of the caliper heads to pivot the caliper heads into a xe2x80x9cclosedxe2x80x9d position to grip the bowstring. As the trigger is depressed, it also forces the piston through the pneumatic chamber, which evacuates air from the chamber through the air vent thereby forming a vacuum in the chamber. With the apparatus in the xe2x80x9cclosedxe2x80x9d position, the archer can then draw the bow and take aim at a target. Once the archer releases the trigger, air will enter the chamber through the air intake control valve, which is adjustable to control the rate at which air enters the chamber. As the chamber refills with air, the piston is urged back through the chamber, thereby pivoting the trigger out of engagement with the wedge-shaped plate and allowing the wedge-shaped plate to disengage from the caliper heads, thereby allowing the caliper heads to resume the xe2x80x9copenxe2x80x9d position and release the bowstring.